Macromolecular Research最新文献

Abstract

The severity of environmental and ecological pollution caused by microplastics has become a prominent global concern. In this study, we prepare biodegradable microplastics to replace primary microplastics used as solid raw materials in personal care and cosmetics, synthesizing them using eco-friendly materials, including polylactic acid (PLA, base material), decyl glucoside and lignin (co-surfactants). Employing a solvent evaporation method, uniform spherical microparticles with an average diameter of approximately 5.5 μm are produced. They are potentially harmless to humans and the environment. During the process, lignin adsorbs onto the surface of PLA through non-covalent interactions, forming Lig@PLA microparticles. Additionally, the aqueous solution used in the process can be reused at least four times, presenting both economic and environmental benefits. The Lig@PLA microparticles exhibit approximately 1.3-fold faster biodegradation and 163 times higher antioxidant activity compared to neat PLA due to the presence of lignin on the PLA surface. Consequently, the biodegradable microplastics developed in this study demonstrate potential for use as solid raw materials in personal care products and cosmetics and offer a promising solution to mitigate environmental and ecological pollution by microplastics.

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Antimicrobial polymers have been intensively studied as a promising strategy to suppress the growth of microbes and mitigate the transmission of pathogens owing to their distinctive properties, such as high molecular weights, tunable structures, functionality, and polyvalency. Unlike the monomers, the repetitive structure and polyvalency of polymers enable robust interactions with the target surfaces to provide synergetic functionality. Antimicrobial polymers have a great variety of adjustable chain lengths and surface chemistry. Furthermore, their backbones can be functionalized with bioactive substituents to interact with cell membranes, lipids, and proteins. The surface coating methods and the resulting antimicrobial activities depend on polymer characteristics, such as the combination of monomers, synthetic methods, contact time, and substrates. This review focuses on representative antimicrobial polymers, including hydrophilic and ionic polymers, polysaccharides, and copolymers containing amine groups and quaternary ammonium cations (QACs). The surface application strategies and antimicrobial properties for each polymer type are also discussed to provide inspiration for the advanced design of antimicrobial polymers.

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Schematic illustration of antifouling- or microbicidal polymers coated on solid surfaces.

Recent advancements in conjugated polymer-based gas sensors have highlighted the critical role of side-chain engineering in optimizing organic field-effect transistor (OFET) performance for gas detection. This review provides a comprehensive analysis of how structural modifications of side chains in conjugated polymers affect the electrical properties of OFETs, as well as the sensitivity and selectivity of OFET-based gas sensors. We first explore modifications of alkyl side chains and their impact on the electrical characteristics of conjugated polymers. Then, we discuss how functionalized side chains and additives can significantly enhance sensor performance by improving detection limits and selectivity. Special attention is given to glycol-based side chains, particularly in enhancing NO₂ sensitivity, and the role of alkyl side chain length in tuning gas sensing capabilities. This review aims to elucidate the intricate relationships between side chain modifications and sensor performance, offering insights for the development of advanced OFET-based gas sensors with improved sensitivity and selectivity.

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The excessive use of disposable chopsticks generates a significant amount of waste, particularly waste bamboo chopsticks (WBC). This study aims to reduce waste and enhance the value of WBC by extracting bamboo fibers and reinforcing them in a biopolymer matrix. Research on WBC/polymer composites, especially those utilizing extracted bamboo fibers in a biopolymer matrix, is limited. In this research, the bamboo fibers extracted from WBC and bamboo plant are reinforced into a biopolymer called polybutylene succinate (PBS) at varying levels from 0 to 40wt% with increments of 10wt%. The characteristics of composites made from WBC fiber and PBS are analyzed and compared with those of PBS incorporating bamboo fibers obtained directly from bamboo plants. The evaluation focuses on various aspects, including morphology, mechanical strength, thermal properties, and rheological characteristics. The results showed that introducing WBC fibers into the PBS matrix did not significantly compromise the properties or thermal stability of the composites when contrasted with bamboo fibers sourced from bamboo plants and used in PBS composites. The WBC fiber/PBS composites displayed slightly superior mechanical and rheological properties compared to composites incorporating bamboo plant fibers in PBS. The results affirm that bamboo fibers extracted from WBC can effectively reinforce biopolymer composites.

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We report that thin-film morphology of sol–gel zinc oxide (ZnO) and their n-doping characteristics can be controlled using polymers, enabling high-performance n-type electrolyte-gated transistors (EGTs). The wrinkled surface of ZnO films was induced by dissolving an insulating polymer, for example, poly(4-vinyl phenol) (PVPh) and poly(2-hydroxyethyl methacrylate) (PHEMA), into the ZnO precursor solutions, followed by drying at 210 °C. The roughness peaked when the polymer composition was 2.5 wt%. The wavelength (λ) of the wrinkling structure was varied depending on the added polymer (0.49 μm for PVPh and 0.74 μm for PHEMA). For n-doping of the ZnO films, polyethylenimine (PEI) was deposited on the composite films, followed by high-temperature annealing at 500 °C. The constituent polymers (PVPh/PHEMA and PEI) were found decomposed after the heat treatment. The resulting n-doped ZnO films showed excellent electrical characteristics when used as a channel layer in EGTs based on a solid-state ion-gel. The device has a high electron mobility of 63.7 cm² V⁻¹ s⁻¹ when ZnO channel was made with 1.0% of PVPh in the precursor.

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Thin films of sol–gel precursors of ZnO mixed with an insulating polymer form wrinkled surface during drying and become more susceptible to n-doping from a nitrogen-rich polymer by thermal annealing, enabling the mobility enhancement of ZnO in electrolyte-gated transistors.

The development of wound-dressing materials with superior therapeutic effects, controlled bioactive agent release, and optimal mechanical properties is crucial in healthcare. This study introduces innovative hydrogel films designed for the sustained release of the local anesthetic drug Procaine (PC), triggered by pH changes. These films are composed of MIL-101(Fe) particles and pectin polymers. MIL-101(Fe) was chosen for its high surface area, stability in aqueous environments, and biocompatibility, ensuring low toxicity to normal cells. MIL-101(Fe)-embedded-pectin hydrogels were synthesized and characterized using Fourier-transformed infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), inductively coupled plasma (ICP) spectrometry, particle size analysis, and goniometry. Rheological analysis assessed the hydrogels’ viscoelastic behavior, and UV-spectrophotometry was utilized for drug loading and release studies. The hydrogels exhibited shear-thinning properties, enhancing shape adaptability and recovery, crucial for wound-dressing applications. Controlled drug release was achieved by maintaining the PC solution’s pH between 8.2 and 9.8 during the drug-loading step. The hydrogel film’s impact on wound healing was evaluated through an in vitro wound healing assay, and cytotoxicity was assessed using a WST-1 cell proliferation assay with human dermal fibroblast cells. Results demonstrated that pectin composites enhance cell viability and support fibroblast cell migration without adverse effects, indicating their potential for effective wound healing applications. This study highlights the potential of MIL-101(Fe)-embedded-pectin hydrogels in advancing wound care technology.

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MIL-101(Fe)-embedded pectin film as wound dressing

Nerve agents, toxic organophosphorus compounds used in chemical warfare, present significant threats to security and public health. These agents disrupt physiological processes by covalently binding to acetylcholinesterase and blocking its ability to break down the neurotransmitter acetylcholine. Despite international efforts to eliminate such weapons, nerve agents continue to be employed due to their ease of production and stability. Their colorless, odorless nature, combined with their rapid action, underscores the importance of developing efficient detection techniques. Traditional detection methods, such as mass spectrometry, rely on the use of bulky, complex equipment and sample preparation procedures. Recent progress in the development of colorimetric and fluorescent probes has enabled direct visual confirmation of nerve agents without the need for such instrumentation. Building on these advancements, we present a turbidity-based approach to detect nerve agent mimics in water. Our method employs a polymer that, upon reacting with a nerve agent mimic, transforms from a water-insoluble polymer to a water-soluble polymer. This change causes a turbid polymer dispersion in water to become clear when exposed to a nerve agent mimic, offering a clear visual signal and a turn-on response in terms of light transmission. The method, which forgoes the need for spectroscopy, represents a platform for the future integration of the transparency-based detection scheme into sensor devices.

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A schematic illustration of the turbidity-based sensing used in this study and the corresponding digital photographs of the opaque dispersion of P1 in water along with photographs taken after the injection of DCNP

The interface is one of the most important factors affecting the macroscopic properties of polymer nanocomposite dielectrics. However, the study of the interface still faces many challenges, such as the evolution mechanism of the interface microstructure, interface compatibility, interface polarization, and the internal mechanism of crystallization. Due to the lack of direct observation and characterization of the interface, the theoretical research is seriously hindered. The influence of the nanoparticles embedded in the nanodielectric and the interfacial region on charge transport and accumulation is still unclear. Since the nanoscale interface is beyond the spatial resolution of traditional analytical techniques, the understanding of the interfacial charge behavior of polymer nanocomposites is largely dependent on speculation and indirect experimental results. Atomic force microscopy (AFM), as a nanometer high-resolution measuring instrument, has become an important means to study the interfacial microregions of polymer nanocomposite dielectrics. In this paper, the latest research progress of various interface models and functional AFM in interface structure, charge transport, and interface polarization are reviewed. The existing problems and possible development directions in the future are also discussed.

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Nanodielectrics show excellent dielectric properties, and many scholars try to explain this phenomenon from different angles, among which, the interface effect between nanoparticles and polymer matrix has aroused great interest of researchers. However, due to the complexity of the interface region, it is impossible to intuitively obtain the microstructure and interaction mechanism between the polymer chain and the nanoparticles in the interface region, so researchers have proposed different interface models to speculate and explain the macroscopic properties of the nanocomposites. Such as diffusion electric double layer model, multi-core model, interphase volume model, double layer model, water shell model, multi-zone structure model, penetration theory model, three-dimensional electrostatic model, deep trap model, etc.

The present work reports formulation of nanohybrids of CuFe₂O₄ using polypyrrole (PPy) in the weight ratios of 1%, 3% and 5%. The synthesized nanohybrids were characterized using FTIR, UV–Vis, XRD and SEM–EDS. The optical band gaps were calculated to be 2.31 eV, 2.11 eV and 1.74 eV for 1-PPy/CuFe₂O₄, 3-PPy/CuFe₂O₄, and 5-PPy/CuFe₂O₄, respectively. The photocatalytic degradation of urea and polyethene (PE) was carried out under visible light irradiation to study the effect of degradation of pollutants in presence of an organic–inorganic hybrid photocatalyst. The nanohybrids showed superior photocatalytic performance when compared with pure CuFe₂O₄. The maximum photocatalytic degradation was found to be 62% within 120 min using 5-Ppy/CuFe₂O₄ as photocatalyst and 40% degradation of PE films was achieved under microwave irradiation. The catalysts showed promising results for the highly efficient degradation of polymers.

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Photocatalytic activity of polypyrrole/copper ferrite nanohybrids

Almost all fabricated polymers need high stabilization to prevent harmful effects. Adding specialized chemicals that rule as light stabilizers (or UV stabilizers) and tailor to the resin's characteristics might accomplish the desired stability. In this work, five antipyrine derivatives were synthesized by the Schiff bases using five benzaldehyde substituents (benzaldehyde, 4-bromobenzaldehyde, 4-nitrobenzaldehyde, 4-dimethylaminobenzaldehyde, and 4-hydroxybenzaldehyde) with 4-aminoantipyrene. The produced complexes are characterized using hydrogen-1 and carbon-13 nuclear magnetic resonance (¹H-NMR and ¹³C-NMR, respectively) and Fourier-transform infrared (FTIR) spectroscopy; then they are filled with polyvinyl chloride (PVC) films. Further techniques are used to study the effects of long-term radiation exposure on these films. The IR spectra of PVC films showed side products containing polyene and carbonyl groups before, during, and after irradiation. The presence of antipyrine derivatives led to a decrease in the intensity of their associated functional groups. Furthermore, it is shown that films with antipyrine compounds performed lower weight loss when exposed to radiation compared with the virgin film.

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